Steel

Vital to the construction and automotive industry. Steel is one of the most recycled metals in the world – yet it is still responsible for a large proportion of global CO² emissions.

Steel

Steel is used in many areas of our lives. It is an important engineering and construction material and can be recycled multiple times without the deterioration of its physical or chemical properties. Primarily composed of iron and carbon, it can also contain metals such as manganese, nickel, titanium, chromium and molybdenum, among others. There are four widely known types of steel: carbon steels, alloy steels, stainless steels and tool steels.

China is by far the largest producer of steel, accounting for more than half of global supply. Large amounts of scrap steel are sourced from a broad range of pre- and post-consumer material streams, as steel is not technically difficult to recycle. Despite the high level of recycling in the steel industry, its huge carbon footprint is a prominent environmental issue.

Main uses and applications

Steel is highly durable and has a low density in comparison to many other materials, making it particularly well suited for construction and automobile manufacture. Steel production has become much more energy efficient in recent years, with modern techniques requiring only 40% of the energy input as compared with manufacturing in the 1960s.

There are a great number of different kinds of steel and multiple ways to categorise them, with one broad classification distinguishing between carbon steels, stainless steels, tool steels and alloy steels. Carbon steels have limited amounts of non-ferrous metals, with a carbon content of up to 2%, with applications in automobile bodies, consumer appliances and wiring. Stainless steels contain chromium as the main alloying metal, typically with a 10% – 20% content, and can be used to manufacture domestic appliances and medical equipment. Tool steels are physically treated to be very hard, strong and heat-resistant, specifically for manufacturing tool. Lastly, alloy steels are a broad family of alloys, which in addition to iron may also contain metals such as: chromium, manganese, molybdenum, silicon, tungsten, vanadium.

Worldwide, more than half of all steel was used for building and infrastructure (52%) in 2020, with other major applications including mechanical equipment (16%), automotives, (12%), metal products (10%), non-automotive transport such as trains and ships (5%), electrical equipment (3%) and domestic appliances (2%). Scrap steel is relatively easy to recycle and can come from multiple different sources, such as automobiles and marine vessels that have reached the end of their lifetime, or buildings that have been demolished. Approximately one fifth of all steel manufactured globally comes from recycled steel.